The Histopathology Core provides a wide spectrum of histology and microscopy services to meet the growing needs of diabetes researchers at Columbia University and affiliated institutions. Over the previous funding cycle, due to ovenwhelming demand for these essential services, the histopathology laboratory (formerly part of the Phenotyping core) and microscopy services (formeriy part of the Genomics core) have been consolidated into a new Histopathology Core. The services of this new core include the high quality basic histological and microscopy services offered in the previous funding cycle, but have been expanded to accommodate the changing and growing needs of DRC users and to incorporate newly developed reagents and technologies. Furthermore, Dr. Sussel, a leader in islet biology and pancreas development was recruited to Columbia University and the Berrie Diabetes Center in 2008 and was enlisted to develop and direct this new core. Since its establishment in 2008, the Histopathology Core has assisted 32 DRC investigators supported by 69 grants and 6 non-DRC investigators on projects that have resulted in 61 papers (29 as primary Core) and/or provided data that helped investigators obtain 14 new grants. It has processed 30,000 samples, cut -300,000 sections and performed 36,000 immunohistochemical stains, nearly 18,000 of which by immunofluorescence. The Core plans to continue to provide advanced histophenotyping capabilities to the thriving Columbia University diabetes research community. To this end, the Core will seamlessly integrated its operation with that of the other DRC Core facilities, to maintain an investigator-oriented approach to service and development, implement and sustain effective business practices, and assist the DRC in its overall mission.